The present invention relates to the scheduling of movement of plural units through a complex movement defining system, and in the embodiment disclosed, to the scheduling of the movement of freight trains over a railroad system, and specifically to the managing the dynamic properties of the plan.
Systems and methods for scheduling the movement of trains over a rail network have been described in U.S. Pat. Nos. 6,154,735, 5,794,172, and 5,623,413, the disclosure of which is hereby incorporated by reference.
As disclosed in the referenced patents and applications, the complete disclosure of which is hereby incorporated herein by reference, railroads consist of three primary components (1) a rail infrastructure, including track, switches, a communications system and a control system; (2) rolling stock, including locomotives and cars; and, (3) personnel (or crew) that operate and maintain the railway. Generally, each of these components are employed by the use of a high level schedule which assigns people, locomotives, and cars to the various sections of track and allows them to move over that track in a manner that avoids collisions and permits the railway system to deliver goods to various destinations.
As disclosed in the referenced patents and applications, a precision control system includes the use of an optimizing scheduler that will schedule all aspects of the rail system, taking into account the laws of physics, the policies of the railroad, the work rules of the personnel, the actual contractual terms of the contracts to the various customers and any boundary conditions or constraints which govern the possible solution or schedule such as passenger traffic, hours of operation of some of the facilities, track maintenance, work rules, etc. The combination of boundary conditions together with a figure of merit for each activity will result in a schedule which maximizes some figure of merit such as overall system cost.
As disclosed in the referenced patents and applications, and upon determining a schedule, a movement plan may be created using the very fine grain structure necessary to actually control the movement of the train. Such fine grain structure may include assignment of personnel by name as well as the assignment of specific locomotives by number, and may include the determination of the precise time or distance over time for the movement of the trains across the rail network and all the details of train handling, power levels, curves, grades, track topography, wind and weather conditions. This movement plan may be used to guide the manual dispatching of trains and controlling of track forces, or provided to the locomotives so that it can be implemented by the engineer or automatically by switchable actuation on the locomotive.
The planning system is hierarchical in nature in which the problem is abstracted to a relatively high level for the initial optimization process, and then the resulting course solution is mapped to a less abstract lower level for further optimization. Statistical processing is used at all levels to minimize the total computational load, making the overall process computationally feasible to implement. An expert system is used as a manager over these processes, and the expert system is also the tool by which various boundary conditions and constraints for the solution set are established. The use of an expert system in this capacity permits the user to supply the rules to be placed in the solution process.
Currently, a dispatcher's view of the controlled railroad territory can be considered myopic. Dispatcher's view and processes information only within their own control territories and have little or no insight into the operation of adjoining territories, or the railroad network as a whole. Current dispatch systems simply implement controls as a result of the individual dispatcher's decisions on small portions of the railroad network and the dispatchers are expected to resolve conflicts between movements of objects on the track (e.g. trains, maintenance vehicles, survey vehicles, etc.) and the available track resource limitations (e.g. limited number of tracks, tracks out of service, consideration of safety of maintenance crews near active tracks) as they occur, with little advanced insight or warning.
A train schedule is an approximate strategic forecast for a train provided by a customer for the desired movements of trains. The train schedule may be made days, weeks or months in advance. The actual train behavior is a function of many factors, such as (a) work to be performed along the route, (b) consist-based constraints (e.g., height, width, weight, speed, hazmat and routing restrictions), (c) re-crew requirements, and (d) the physics of the train and locomotive consist. These factors vary from day to day and for the same train along its route.
The movement plan for trains cannot be accurate in the absence of this information, which is available to the railroad, but is generally not available in sufficient detail for the movement planner. If the movement planner is not provided with the needed information, including dynamic variation in time and route, train movement will be planned and auto routed in a manner inconsistent with the then-current conditions. For example, if a block is placed in front of a train and the movement planner has not received this information, the movement plan may route the train to a location it cannot advance out of.
Typically, prior art movement planners calculate movement plans from static train schedules and fixed train priorities. Train characteristics are not forecast at all points along the planned route; instead the plan is typically based on default characteristics, characteristics applicable at the current location of the train, or characteristics assumed upon terminal departures. Line of the road and terminal attributes are treated as constant throughout the planning process to simply the complexity of the scheduling problem, and due to a lack of coordination in data collection from the railroad, dispatcher and filed sensors.
The present disclosure provides a database of train characteristics derived from the railroad's management information systems, field sensors and dispatch input to provide an improved movement plan that reflects the most current characteristics of the train and attributes of the line or road.
These and many other objects and advantages of the present invention will be readily apparent to one skilled in the art to which the invention pertains from a perusal of the claims, the appended drawings, and the following detailed description of the embodiments.